C# 内存法图像处理

8/3/2015来源:C#应用人气:1484

C# 内存法图像处理

内存法通过把图像储存在内存中进行处理,效率大大高于GetPixel方法,安全性高于指针法。

笔者当初写图像处理的时候发现网上多是用GetPixel方法实现,提到内存法的时候也没有具体实现,所以笔者在这里具体实现一下- -,望指正。

首先讲一下用到的一些方法。

1.LockBits和UnlockBits:使用 LockBits方法,可在系统内存中锁定现有的位图,以便通过编程方式进行更改,每调用LockBits之后都应该调用一次UnlockBits。

2.Scan0:图像的第一个字节地址。

3.Stride:步幅,扫描宽度,形象的说就是一行的长度。

4.PixelFormat:数据的实际像素格式。

给出原图:

一、灰度

对每个像素点进行加权平均,(方法不唯一)。

        /// <summary>        /// 灰化实现方法        /// </summary>        void Image_Ashing()        {            if (pbshowbox.Image != null)            {                int Height = this.pbshowbox.Image.Height;                int Width = this.pbshowbox.Image.Width;                Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format24bpPRgb);                Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;                BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format24bppRgb);                BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format24bppRgb);                unsafe                {                    byte* pin = (byte*)(oldData.Scan0.ToPointer());                    byte* pout = (byte*)(newData.Scan0.ToPointer());                    for (int y = 0; y < oldData.Height; y++)                    {                        for (int x = 0; x < oldData.Width; x++)                        {                            byte Result = (byte)(pin[0] * 0.1 + pin[1] * 0.2 + pin[2] * 0.7);//加权平均实现灰化                            pout[0] = (byte)(Result);                            pout[1] = (byte)(Result);                            pout[2] = (byte)(Result);                            pin = pin + 3;                            pout = pout + 3;                        }                        pin += oldData.Stride - oldData.Width * 3;                        pout += newData.Stride - newData.Width * 3;                    }                    bitmap.UnlockBits(newData);                    MyBitmap.UnlockBits(oldData);                    this.pbshowbox.Image = bitmap;                }            }            else            {                MessageBox.Show("请先打开一张图片!");            }        }

二、柔化

像素点与周围像素点差别较大时取平均值。

        /// <summary>        /// 柔化实现方法        /// </summary>        void Image_Soften()        {            if (pbshowbox.Image != null)            {                int Height = this.pbshowbox.Image.Height;                int Width = this.pbshowbox.Image.Width;                Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format32bppRgb);                Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;                BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppRgb);                BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format32bppRgb);                unsafe                {                    byte* pin = (byte*)(oldData.Scan0.ToPointer());                    byte* pout = (byte*)(newData.Scan0.ToPointer());                    //高斯模板                    int[] Gauss = { 1, 2, 1, 2, 4, 2, 1, 2, 1 };                    for (int i = 1; i < Width - 1; i++)                    {                        for (int j = 1; j < Height - 1; j++)                        {                            int r = 0, g = 0, b = 0;                            int Index = 0;                            for (int col = -1; col <= 1; col++)                            {                                for (int row = -1; row <= 1; row++)                                {                                    int off = ((j + row) * (Width) + (i + col)) * 4;                                    r += pin[off + 0] * Gauss[Index];                                    g += pin[off + 1] * Gauss[Index];                                    b += pin[off + 2] * Gauss[Index];                                    Index++;                                }                            }                            r /= 16;                            g /= 16;                            b /= 16;                            //处理颜色值溢出                            if (r < 0) r = 0;                            if (r > 255) r = 255;                            if (g < 0) g = 0;                            if (g > 255) g = 255;                            if (b < 0) b = 0;                            if (b > 255) b = 255;                            int off2 = (j * Width + i) * 4;                            pout[off2 + 0] = (byte)r;                            pout[off2 + 1] = (byte)g;                            pout[off2 + 2] = (byte)b;                        }                    }                    bitmap.UnlockBits(newData);                    MyBitmap.UnlockBits(oldData);                    this.pbshowbox.Image = bitmap;                }            }            else            {                MessageBox.Show("请先打开一张图片!");            }        }

三、锐化

突出显示颜色值大的像素点。

        /// <summary>        /// 锐化实现方法,显示数值最大像素点        /// </summary>        void Image_Sharpen()        {            if (this.pbshowbox.Image != null)            {                int Height = this.pbshowbox.Image.Height;                int Width = this.pbshowbox.Image.Width;                Bitmap bitmap = new Bitmap(Width, Height, PixelFormat.Format32bppRgb);                Bitmap MyBitmap = (Bitmap)this.pbshowbox.Image;                BitmapData oldData = MyBitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadOnly, PixelFormat.Format32bppRgb);                BitmapData newData = bitmap.LockBits(new Rectangle(0, 0, Width, Height), ImageLockMode.ReadWrite, PixelFormat.Format32bppRgb);                unsafe                {                    byte* pin = (byte*)(oldData.Scan0.ToPointer());                    byte* pout = (byte*)(newData.Scan0.ToPointer());                    //拉普拉斯模板                    int[] Laplacian = { -1, -1, -1, -1, 9, -1, -1, -1, -1 };                    for (int i = 1; i < Width - 1; i++)                    {                        for (int j = 1; j < Height - 1; j++)                        {                            int r = 0, g = 0, b = 0;                            int Index = 0;                            for (int col = -1; col <= 1; col++)                            {                                for (int row = -1; row <= 1; row++)                                {                                    int off = ((j + row) * (Width) + (i + col)) * 4;                                    r += pin[off + 0] * Laplacian[Index];                                    g += pin[off + 1] * Laplacian[Index];                                    b += pin[off + 2] * Laplacian[Index];                                    Index++;                                }                            }                            if (r < 0) r = 0;                            if (r > 255) r = 255;                            if (g < 0) g = 0;                            if (g > 255) g = 255;                            if (b < 0) b = 0;                            if (b > 255) b = 255;                            int off2 = (j * Width + i) * 4;                            pout[off2 + 0] = (byte)r;                            pout[off2 + 1] = (byte)g;                            pout[off2 + 2] = (byte)b;                        }                    }                    bitmap.UnlockBits(newData);                    MyBitmap.UnlockBits(oldData);                    this.pbshowbox.Image = bitmap;                }            }